Hearing aid



FIG. 1 is a perspective view of the hearing aid showing my new design;

FIG. 2 is a front side view thereof;

FIG. 3 is a rear side view thereof;

FIG. 4 is a left side view thereof, the right side view being a mirrorimage thereof;

FIG. 5 is a top plan view thereof; and,

FIG. 6 is a bottom plan view thereof.

The broken lines in FIG. 3 are included for the purpose of illustratinga portion of the hearing aid that forms no part of the claimed design

The ornamental design for a hearing aid, as shown and described.